Mr Sharpe said it would also be a hot Christmas Eve across much of southwestern Queensland.

"A trough will bring a cool change to southeastern Australia, leading to a cool day with a few showers in parts of Victoria and Tasmania," Mr Sharpe said.

"A tropical low or tropical cyclone could sit off the northwest shelf, while Perth and much of Western Australia will be dry and warm-to-hot."

Brisbane can expect cooler weather on Boxing Day, but with the chance of showers or a thunderstorm.

Mr Sharpe said the trough is expected to shift further north in NSW, increasing heat in Queensland, while storms will remain over inland NSW.

"Sydney is now likely to see a shower or two in southerly winds," he said.

"It will be warmer and still mostly sunny on the west coast."

Those living in Perth, Canberra and Adelaide on the other hand can expect the best of the festive weather.

Social analysis company McCrindle Research has crunched the numbers and concluded these capitals have the best chance of perfect Christmas weather.

Based on more than 70 years of date from the Bureau of Meteorology, McCrindle have worked out all three cities have an average temperature of the late 20s with more than an 80 per cent chance of no rain.

Adelaide, Perth and Canberra look like having the best weather, statistics show. Picture: Courtesy McCrindle Research